This invention is directed to a baler (commonly known as "round baler") for forming cylindrical bales and having a bale forming chamber defined by a plurality of belts trained about a plurality of rolls and more particularly, to an automatic mechanism with a manual override for wrapping twine around bales formed in the chamber.
Semiautomatic twine wrapping mechanisms for round balers for agricultural crops are well known. One commercially available wrapping mechanism is similar to that disclosed in U.S. Pat. Nos. 3,894,484 and 3,913,473. The mechanism comprises generally a hydraulically driven twine arm which is movable back and forth in front of an entrance to the bale forming chamber. Initiation and termination of the twine wrapping cycle is manually controlled. The rate of advance of the arm transversely of the bale forming chamber is subject to manual control by the adjustment of the flow control valve in the hydraulic circuit. Following extended commercial use, certain disadvantages for this mechanism have been noted. First, it is desirable to provide automatic (rather than semiautomatic) initiation and termination of the twine wrapping cycle. Heretofore, the operator monitored a bale size gauge on the front of the baler from the operator's position on the tractor pulling the baler. When the bale reached the desired size, the operator then continued baling and pulled a hydraulic lever to actuate movement of the twine arm from a first side of the baler to the second. When the twine is fed with the crop material into the bale forming chamber, the tractor is stopped to discontinue feeding crop into the chamber. The lever is retained in is shifted position until the twine arm reached the second side and held there to allow one or more turns of twine to go around the end of the bale. Then, the hydraulic lever is shifted back to the first side of the baler. The rate of movement of the twine arm from the second to the first side of the baler and therefore the number of wraps of twine around the bale is controlable by adjustment of the flow control valve in the hydraulic circuit. The rate of flow is adjusted such that at least one full wrap of twine is formed around the end of the bale. The twine is then automatically cut. With the automation of such procedure, the burden on the operator of monitoring the operation of the machine behind him from his position in front of the tractor would, of course, be relieved.
It is also known to provide a fully automated twine wrapping mechanism using a mechanical drive from the PTO to drive a pair of twine arms transversely of the bale forming chamber. See, for example, U.S. Pat. No. 4,167,844.
Further, it is known to provide a fully automated twine wrapping system using a spring drive for moving a single twine arm from a first side to the second side of the baler and a hydraulic drive for moving the twine arm from the second side back to the first side. See U.S. Pat. No. 4,150,614.
In accordance with U.S. application, Ser. No. 303,274, cross referenced above, a fully automated hydraulically driven twine wrapping mechanism is disclosed. The wrapping mechanism includes a twine wrapping control mechanism which automatically controlled the actuation of the hydraulic pump and the control valve of the hydraulic drive means for the twine dispensing mechanism. The control mechanism further includes an adjustable length bale diameter sensing link which could be preset to determine the diameter at which the wrapping mechanism would be actuated.
Actuation is accomplished by stretching a pair of springs to energize the hydraulic drive means when the springs are fully stretched. The full stretch of the springs causes the release of a latch to relieve the tension on one of the springs to actuate the drive for the hydraulic pump. However, the sensing links had a limited range of adjustability. In addition, no means were provided for manually overriding the twine wrapping control mechanism and thus, the flexibility of an operator to actute the wrapping mechanism at his option such as may be desirable, for example, on the completion of baling in a field was limited to the setting of the sensing link.
It is known to provide a round baler with a twine wrapping mechanism which is adapted to the actuated either manually or automatically by a power motor such as a hydraulic cylinder. See U.S. Pat. No. 4,072,095.
Accordingly, it is an object of this invention to provide an improved fully automated hydraulically driven twine wrapping mechanism with a twine wrapping control mechanism with a manual override and to wrap a bale at a selected diameter irrespective of the diameter preset for actuation of the twine wrapping mechanism.
Another object of the invention is to provide a twine wrapping mechanism with a single manual override control linkage for cycling the twine dispensing mechanism through a second cycle and for actuating the wrapping mechanism to wrap a bale at a selected diameter irrespective of the diameter preset for actuation of the twine wrapping mechanism.
Still another object is to provide a twine wrapping control mechanism which controls actuation of a latch for the pump drive independently of tension springs for shifting a hydraulic drive means and a hydraulic valve control arm.